Published by: Ingrid King. Last Updated on: June 29, 2023 by Crystal Uys


In January, I wrote about the benefits of vitamin B12 supplementation for cats. At that time, I started Allegra on daily supplementation with Jackson Galaxy’s vitamin B 12 product, and I’m happy to say that it has made a noticeable difference for her.

Signs of vitamin B12 deficiency

Not having enough B12 can cause weight loss, lethargy, diarrhea, or vomiting.

Gastrointestinal disorders such as inflammatory bowel disease can interfere with the absorption of B12. B12 is water soluble and only stays in the body for a limited time. In a healthy cat, the tissues retain B12 for an average of 13 days, but in a cat with gastrointestinal disease or other health problems, B12 may stay in the body for only about 5 days. This quick depletion can cause low B12 levels. (Source: Vitamin B12 Deficiency in Cats: The Role of the Gut.) Measuring B12 levels in your cat’s blood can be a good indicator of overall gut health.

Vitamin B12 supplementation

There are two forms of Vitamin B12, methylcobalamine and cyanocobalamin. Methylcobalamine is more readily absorbed when given orally as a supplement. Vitamin B12 can also be given as a subcutaenous injection.


Jackson Galaxy B12 for Cats Dietary Supplement

Jackson Galaxy developed a B12 supplement for cats that contains only methylcobalamine, no fructose, fillers or artificial ingredients. The supplement can help to

    • boost immunity
    • maintain or improve gastrointestinal health
    • maintain kidney health
    • keep the nervous system functioning optimally
    • keep the pancreas healthy
    • increase appetite

Putting Vitamin B12 to the test

Allegra has not been showing any signs of vitamin B12 deficiency, but she has had mild, undefined gastrointestinal symptoms for quite some time. She’ll occasionally vomit up some water or undigested food. Since the episodes are rare and mild, my vet and I are taking a watch and wait approach rather than putting her through diagnostics other than regular blood tests to monitor her thyroid. Since starting the Vitamin B12 about a month ago, these episodes have been getting even less frequent, so I’m pretty sure it’s making a difference for her. Since she’s hyperthyroid, I’m also concerned about maintaining her kidney health.

The supplement should be given with food. I never mix anything in with a regular meal until I’ve tried it with a small amount of food first. Mixing something in with food can inadvertently create a food aversion if it doesn’t taste good to your cat. She may then decide that something is wrong with her food, and you’ll end up with a finicky eater.

I give Allegra her Vitamin B with a little bit of a Churu treat. I drizzle the B12 on a small plate, top it with half a tube of Churu, and she laps it all up.

Allegra’s most recent bloodwork, done about two weeks after I started the Vitamin B12, showed perfect values all around.

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